In the fabrication of implosion-resistant cathode ray tube structures, it has been a common practice to provide a pair of rimbands which are placed in contact with the flanged portion of a substantially rectangular-shaped viewing portion of an evacuated envelope. Ear members suitable for attachment to bolts for supporting the cathode ray tube are welded or otherwise attached to the rimbands. Thereafter a metal band member encircles and exerts a compression force on the rimbands and affixed ear members.
Ordinarily, the rimbands and ear members are fabricated from a material such as cold rolled steel and the ear members are affixed to the rimbands. Since the parts are frequently stored for extended periods prior to use, there is a tendency toward undesired rusting and discoloration. However, such conditions were substantially overcome by attaching the ear members to the rimbands and then applying a coating of a material such as zinc to the attached parts prior to storage.
Unfortunately, it has been found that the above-described technique of welding uncoated ear members to uncoated rimbands and then coating the already affixed parts is a most inefficient technique. Particularly, the individual parts are usually decreased at one location, shipped to another for welding, shipped to still another location for plating, returned to the manufacturer for inspection, and finally provided to the factory fabricating the implosion-resistant cathode ray tube structures. Obviously, such complex handling requires an extended lead time and emergency situations at the cathode ray tube manufacturing facility are frequent due to the unavailability or delay in delivery of the required components.
One suggestion for alleviating the above-mentioned undesirable conditions is to provide pre-plated ear members and rimbands. In this manner, the individual parts could be stored for extended periods of time without fear of rust and similar undesirable conditions. Moreover, the pre-plated parts could be readily combined to provide the desired rimband and ear member combinations required.
Unfortunately, prior known techniques for welding plated ear members to plated rimbands have resulted in undesired disfigurement of the ear members. As a result, it was found that the undesired disfigurement or distortions of the ear member tended to inhibit the application of the tensioned metal band. As the metal band was tightened to obtain the desired compressive force, the distortions of the ear member caused an undesirable resistance and the necessary and desirable amount of tension on the rimband was either reduced or unattainable with prior known welded structures of plated materials.